Liquid crystal display panel

ABSTRACT

A liquid crystal display panel includes a first substrate section having a first substrate and pixel electrodes ( 102 ). Each pixel electrode ( 102 ) includes a bridging portion ( 102   c ) provided between a first pixel electrode portion ( 102   a ) and a second pixel electrode portion ( 102   b ) and linking together the first pixel electrode portion ( 102   a ) and the second pixel electrode portion ( 102   b ). A first recess ( 102   d ) is provided at one side along the width direction of the pixel electrode ( 102 ), the first recess ( 102   d ) extending from one side along the width direction of the pixel electrode ( 102 ) toward the bridging portion ( 102   c ) and being located between the first pixel electrode portion ( 102   a ) and the second pixel electrode portion ( 102   b ). A second recess ( 102   e ) is provided at another side along the width direction of the pixel electrode ( 102 ), the second recess ( 102   e ) extending from the other side along the width direction of the pixel electrode ( 102 ) toward the bridging portion ( 102   c ) and being located between the first pixel electrode portion ( 102   a ) and the second pixel electrode portion ( 102   b ).

TECHNICAL FIELD

This invention relates to a liquid crystal display panel whose displaymode is a VA mode.

BACKGROUND ART

A liquid crystal display apparatus is a display apparatus which performsdisplay by utilizing a liquid crystal composition. Under onerepresentative displaying method, a liquid crystal composition is sealedin between a pair of substrates; a liquid crystal display panelincluding this pair of substrates and the liquid crystal composition,these being sandwiched between a pair of polarizers, is irradiated withlight from a backlight; and a voltage is applied to the liquid crystalcomposition in order to change the alignment of the liquid crystalmolecules, whereby the amount of light passing through the liquidcrystal display panel is controlled. Such a liquid crystal displayapparatus has advantages such as a thin profile, light weight, and lowpower consumption, and therefore is utilized in smartphones, tablet PCs,car navigation systems, and other electronic devices.

In some conventional liquid crystal display panels, one pixel is dividedinto a plurality of domains (alignment regions), such that liquidcrystal molecules are aligned in a different azimuth in each domain,thereby improving viewing angle characteristics. Examples of the methodof achieving such alignment division in a pixel are methods that dividea half pixel into four domains of two rows by two columns; currently, a4D-RTN (4Domain-Reverse Twisted Nematic) mode of Patent Documents 1 and2, and a 4D-ECB (4Domain-Electrically Controlled Birefringence) mode ofPatent Document 2, and the like are under study.

At a boundary between regions of different alignment azimuths of liquidcrystal molecules, owing to continuity of the liquid crystal molecules,there are always portions where the alignment direction of liquidcrystal molecules is parallel to the polarization axis of one of thepolarizers. When liquid crystal displaying is performed in such a state,the aforementioned portions are visible as dark lines because no lightis transmitted therethrough, and thus the transmittance and contrastratio are reduced.

FIG. 14 is a schematic plan view showing one pixel, illustrating anexemplary region in which a dark line 1120 may occur in the liquidcrystal display panel of Patent Document 3.

In the aforementioned liquid crystal display panel of Patent Document 3,one pixel is divided into four domains of one column by four rows. Morespecifically, a pixel 1000 includes four domains 1000 a, 1000 b, 1000 cand 1000 d in which liquid crystal molecules 1041 have mutuallydifferent alignment azimuths (azimuths of tilt). The domains 1000 a,1000 b, 1000 c and 1000 d are arranged along the longitudinal directionof the pixel 1000 (i.e., the up-down direction in FIG. 14). Herein, whenan azimuth flush with the transverse direction of the pixel 1000 (i.e.,the right-left direction in FIG. 14) is defined as 0°, an alignmentazimuth of the liquid crystal molecules 1041 in the domain 1000 a is45°; an alignment azimuth of the liquid crystal molecules 1041 in thedomain 1000 b is 225°; an alignment azimuth of the liquid crystalmolecules 1041 in the domain 1000 c is 135°; and an alignment azimuth ofthe liquid crystal molecules 1041 in the domain 1000 d is 315°.

Since the alignment azimuth of the liquid crystal molecules 1041 in thedomain 1000 a is different from the alignment azimuth of the liquidcrystal molecules 1041 in the domain 1000 b, a portion 1120 b of thedark line 1120 extends along the boundary between the domain 1000 a andthe domain 1000 b.

Moreover, since the alignment azimuth of the liquid crystal molecules1041 in the domain 1000 c is different from the alignment azimuth of theliquid crystal molecules 1041 in the domain 1000 d, another portion 1120a of the dark line 1120 extends along the boundary between the domain1000 c and the domain 1000 d.

What is depicted at 1011 in FIG. 14 is a wiring line.

CITATION LIST Patent Literature

[Patent Document 1] Japanese Patent No. 5184618

[Patent Document 2] Japanese Laid-Open Patent Publication No. 2011-85738

[Patent Document 3] International Publication No. 2017/047532

SUMMARY OF INVENTION Technical Problem

The inventors have studied alignment azimuths of the liquid crystalmolecules 41 in the four domains 1000 a, 1000 b, 1000 c and 1000 d tofind that, from the standpoint of enhancing the transmittance of pixels,it is preferable to set the alignment azimuths of the liquid crystalmolecule 1041 in the domains 1000 a, 1000 b, 1000 c and 1000 d to 135°,225°, 45° and 315°, or to 45°, 315°, 135° and 225°.

However, setting the alignment azimuths of the liquid crystal molecule1041 in the domains 1000 a, 1000 b, 1000 c and 1000 d to 135°, 225°, 45°and 315°, or to 45°, 315°, 135° and 225°, results in the problem of anincreased geometric area being occupied by a dark line(s) occurring nearthe boundary between the domain 1000 b and the domain 1000 c, such thatan adequate transmittance cannot be attained.

Therefore, a problem to be solved by this invention is to provide aliquid crystal display panel that can attain an adequate transmittancewith a simple configuration.

Solution to Problem

A liquid crystal display panel according to one implementation of thisinvention is a liquid crystal display panel having a display mode thatis a VA mode, comprising:

a plurality of rectangular-shaped pixels;

a first substrate section including a first substrate and pixelelectrodes;

a liquid crystal layer provided on the first substrate section, theliquid crystal layer containing liquid crystal molecules; and

a second substrate section provided on the liquid crystal layer, thesecond substrate section including a second substrate and a counterelectrode, wherein,

the plurality of pixels each include a first domain, a second domain, athird domain, and a fourth domain arranged along a longitudinaldirection of the pixel,

when a direction orthogonal to the longitudinal direction of the pixelis defined as a transverse direction of the pixel and an azimuth flushwith the transverse direction of the pixel is defined as 0°, analignment azimuth of the liquid crystal molecules in the second domainis substantially 225° and an alignment azimuth of the liquid crystalmolecules in the third domain is substantially 45°; or an alignmentazimuth of the liquid crystal molecules in the second domain issubstantially 315° and an alignment azimuth of the liquid crystalmolecules in the third domain is substantially 135°,

each pixel electrode includes

a first pixel electrode portion facing the first and second domains in athickness direction of the pixel electrode,

a second pixel electrode portion facing the third and fourth domains inthe thickness direction of the pixel electrode, and

a bridging portion being provided between the first pixel electrodeportion and the second pixel electrode portion and linking together thefirst pixel electrode portion and the second pixel electrode portion;

a first recess is provided at one side along a width direction of thepixel electrode, the first recess extending from the one side along thewidth direction of the pixel electrode toward the bridging portion andbeing located between the first pixel electrode portion and the secondpixel electrode portion; and

a second recess is provided at another side along the width direction ofthe pixel electrode, the second recess extending from the other sidealong the width direction of the pixel electrode toward the bridgingportion and being located between the first pixel electrode portion andthe second pixel electrode portion.

Herein, the aforementioned alignment azimuth of a liquid crystalmolecule refers to, in a plan view of the liquid crystal molecule underan applied voltage across the liquid crystal layer, a direction from oneend of the liquid crystal molecule along its major axis direction thatis at the first substrate section side to the other end of the liquidcrystal molecule along its major axis direction that is at the secondsubstrate section side. In this case, when the alignment azimuth of aliquid crystal molecule is said to be 0°, this alignment azimuthcorresponds to the rightward direction from one end of the liquidcrystal molecule along its major axis direction that is at the firstsubstrate section side (so-called the 3 o'clock direction). In thatcase, when the alignment azimuth of a liquid crystal molecule is said tobe 45°, this alignment azimuth corresponds to an alignment azimuth thatresults through a 45° counterclockwise rotation from the 0° alignmentazimuth of the liquid crystal molecule.

As referred to above, substantially 45° means an angle in the range from30° to 60°, or an angle in the range from 40° to 50°. As referred toabove, substantially 135° means an angle in the range from 150° to 120°,or an angle in the range from 140° to 130°. As referred to above,substantially 225° means an angle in the range from 210° to 240°, or anangle in the range from 220° to 230°. As referred to above,substantially 315° means an angle in the range from 300° to 330°, or anangle in the range from 310° to 320°.

Advantageous Effects of Invention

Owing to the aforementioned bridging portion and first and secondrecesses, a liquid crystal display panel according to this invention canattain an adequate transmittance with a simple configuration.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 A schematic cross-sectional view of a liquid crystal displaypanel according to a first embodiment of the present invention.

FIG. 2 A schematic plan view of the liquid crystal display panelaccording to the first embodiment.

FIG. 3 A schematic perspective view for describing the attitudes ofliquid crystal molecules according to the first embodiment.

FIG. 4 An enlarged plan view of a pixel electrode according to the firstembodiment and its neighborhood.

FIG. 5 A photographic representation of a simulation of dark lines inthe first embodiment.

FIG. 6 An enlarged plan view of a pixel electrode according toComparative Example for this invention and its neighborhood.

FIG. 7 A photographic representation of a simulation of dark lines inthe aforementioned Comparative Example.

FIG. 8 An enlarged plan view of a pixel electrode according to avariation of the first embodiment and its neighborhood.

FIG. 9 A photographic representation of a simulation of dark lines inthe aforementioned variation.

FIG. 10 An enlarged plan view of a pixel electrode according to a secondembodiment of this invention and its neighborhood.

FIG. 11 A photographic representation of a simulation of dark lines inthe second embodiment.

FIG. 12 An enlarged plan view of a pixel electrode according to avariation of the second embodiment and its neighborhood.

FIG. 13 A photographic representation of a simulation of dark lines inthe aforementioned variation.

FIG. 14 A schematic plan view for describing a dark line in aconventional liquid crystal display panel.

DESCRIPTION OF EMBODIMENTS

Hereinafter, by way of embodiments illustrated in the drawings, liquidcrystal display panels according to this invention will be described inmore detail. In the drawings, common portions are denoted by likenumerals, with any redundant description being omitted.

First Embodiment

FIG. 1 is a cross-sectional view schematically showing a cross sectionof a liquid crystal display panel according to a first embodiment ofthis invention.

The liquid crystal display panel is a liquid crystal display panel whosedisplay mode is a VA mode, including: a first substrate section 10; afirst vertical alignment film 20; a liquid crystal layer 30 containingliquid crystal molecules 41 (shown in FIG. 2 and FIG. 3); a secondvertical alignment film 40; and a second substrate section 50. The firstvertical alignment film 20, the liquid crystal layer 30, the secondvertical alignment film 40, and the second substrate section 50 arestacked in this order on the first substrate section 10. Between thefirst vertical alignment film 20 and the second vertical alignment film40, a sealing member 90 with which to seal the liquid crystal layer 30is provided. Herein, light from the first substrate section 10 sidepasses through the liquid crystal layer 30, and thereafter travelstoward the second substrate section 50 side. In other words, theaforementioned light enters into the liquid crystal display panel andthen goes out from the liquid crystal display panel at the secondsubstrate section 50 side.

The first substrate section 10 includes a first glass substrate 11 andpixel electrodes 102 provided on an upper surface of the first glasssubstrate 11. Also, thin film transistors 13 (shown in FIG. 3 and FIG.4) are provided on the upper surface of the first glass substrate 11,the thin film transistors 13 being electrically connected to the pixelelectrodes 102. Under the first substrate section 10, a first polarizer60 is disposed. Note that the first glass substrate 11 is an example ofa first substrate.

The second substrate section 50 includes a second glass substrate 51, acolor filter 52, and a counter electrode 103. Along the thicknessdirection of the second glass substrate 51, the color filter 52 isopposed to the pixel electrodes 102. On the second substrate section 50,a second polarizer 70 having a polarization axis that is orthogonal to apolarization axis (transmission axis) of the first polarizer 60 isdisposed. Note that the second glass substrate 51 is an example of asecond substrate.

The pixel electrodes 102 and the counter electrode 103 may each be atransparent electrode of ITO (Indium Tin Oxide), for example.

FIG. 2 is a plan view schematically showing the liquid crystal displaypanel. In FIG. 2, liquid crystal molecules 41 under an applied voltageacross the liquid crystal layer 30 are depicted by cone shapes. Morespecifically, one end of each liquid crystal molecule 41 along its majoraxis direction that corresponds to the apex of the cone is located atthe first substrate section 10 side. On the other hand, the other end ofeach liquid crystal molecule 41 along the major axis direction thatcorresponds to the bottom of the cone is located at the second substratesection 50 side.

In the liquid crystal display panel, a plurality of rectangular-shapedpixels 101 are arranged in a matrix. Each pixel 101 includes fourdomains 100 a, 100 b, 100 c and 100 d, which differ from one another interms of the alignment azimuth of the liquid crystal molecules 41.Moreover, the domains 100 a, 100 b, 100 c and 100 d are arranged alongthe longitudinal direction of the pixel 101 (i.e., the up-down directionin FIG. 2). Note that the domain 101 a is an example of a first domain;the domain 101 b is an example of a second domain; the domain 101 c isan example of a third domain; and the domain 101 d is an example of afourth domain.

When the liquid crystal display panel is viewed from the secondsubstrate section 50 side, assuming that a direction that is orthogonalto the longitudinal direction of each pixel 101 is defined as thetransverse direction of the pixel 101 (i.e., the right-left direction inFIG. 2) and that an azimuth along this transverse direction is definedas 0°, then an alignment azimuth of the liquid crystal molecules 41 inthe domain 101 a is substantially 135°; an alignment azimuth of theliquid crystal molecules 41 in the domain 101 b is substantially 225°;an alignment azimuth of the liquid crystal molecules 41 in the domain101 c is substantially 45°; and an alignment azimuth of the liquidcrystal molecules 41 in the second domain is substantially 315°. Thesealignment azimuths may be conferred by irradiating a photoalignment filmwith polarized UV light through a mask, for example.

Moreover, in order to enhance the transmittance of the liquid crystallayer 30, the transverse direction of the pixel 101 is set so as to beparallel to the polarization axis of the first polarizer 60.

Herein, the alignment azimuth of a liquid crystal molecule 41 is anorientation that does not take into account any tilt angle (pretiltangle) with respect to the normal direction of the upper surface of thefirst glass substrate 11. More specifically, the alignment azimuth of aliquid crystal molecule 41 means a direction in which the other end(i.e., the end at the second substrate section 50 side) of the liquidcrystal molecule 41 along its major axis direction is oriented, when theliquid crystal molecule 41 is projected onto the upper surface of thefirst glass substrate 11, i.e., when the liquid crystal molecule 41 isviewed from the second substrate section 50 side. For example, theliquid crystal molecule 41 are arranged in such a manner that: if thecrystal orientation of a liquid crystal molecule 41 is 10°, when thatliquid crystal molecule 41 is viewed from the second substrate section50 side, the other end of the liquid crystal molecule 41 along its majoraxis direction constitutes 10° with respect to a direction parallel tothe transverse direction of the pixel 101. Note that any angle in acounterclockwise direction with respect to the direction parallel to thetransverse direction of the pixel 101 is assumed to have a positivevalue.

As referred to above, substantially 45° means an angle in the range from30° to 60°, or an angle in the range from 40° to 50°. As referred toabove, substantially 135° means an angle in the range from 150° to 120°,or an angle in the range from 140° to 130°. As referred to above,substantially 225° means an angle in the range from 210° to 240°, or anangle in the range from 220° to 230°. As referred to above,substantially 315° means an angle in the range from 300° to 330°, or anangle in the range from 310° to 320°.

In FIG. 2, a gate line extending along the transverse direction of thepixels 101 is depicted at 14.

FIG. 3 is a schematic perspective view for describing the attitudes ofthe liquid crystal molecules 41 under an applied voltage across theliquid crystal layer 30.

In the domain 101 a, the liquid crystal molecules 41 have an essentiallyconstant pretilt angle between the pixel electrode 102 and the counterelectrode 103. Similarly, in each of the domains 101 b, 101 c and 101 d,the liquid crystal molecules 41 have an essentially constant pretiltangle between the pixel electrode 102 and the counter electrode 103.

A plurality of pixel electrodes 102 are disposed in a matrix, so as tobe in rectangular-shaped regions. Each such region is a region that isdelineated by a plurality of gate lines 14, 14, . . . , which areparallel to one another and a plurality of source lines 15, 15, . . . ,which are parallel to one another.

The gate lines 14, 14, . . . are provided on the first glass substrate11, and extend along a direction which is parallel to the transversedirection of the pixels 101. Moreover, each gate line 14 is electricallyconnected to gates of thin film transistors 13.

The source lines 15 are provided on the first glass substrate 11, andextend along a direction which is parallel to the longitudinal directionof the pixels 101. Moreover, each source line 15 is electricallyconnected to sources of thin film transistors 13.

As the thin film transistors 13, those having channels made by usingsilicon or an oxide semiconductor are suitably used, for example. Assuch an oxide semiconductor, for example, a compound composed of indium,gallium, zinc, and oxygen (In—Ga—Zn—O), a compound composed of indium,tin, zinc, and oxygen (In—Tin-Zn—O), or a compound composed of indium,aluminum, zinc, and oxygen (In—Al—Zn—O) can be used.

As the gate lines 14 and the source lines 15, those which are commonlyused in the field of liquid crystal display panels can be used, e.g., ametal such as copper, titanium, chromium, aluminum, or molybdenum, or analloy thereof, etc.

The color filter 52 is composed of red color filters 52A, green colorfilters 52B, and blue color filters 52C. The red color filters 52A, thegreen color filters 52B, and the blue color filters 52C are each locatedabove a plurality of pixel electrodes 102 that are arranged along thelongitudinal direction of the pixels 101, and extend along thelongitudinal direction of the pixels 101.

FIG. 4 is an enlarged plan view of a pixel electrode 102 and itsneighborhood.

A drain of the thin film transistor 13 is electrically connected to adrain line 16. The drain line 16 is electrically connected also to thepixel electrode 102, via an electrical conductor in a contact hole 17.

Within each rectangular-shaped region that is delineated by the gatelines 14, 14, . . . and the source lines 15, 15, . . . , a capacitorline 18 is also formed. The capacitor line 18 is formed so as to extendalong three sides of the pixel electrode 102, and is electricallyconnected to the pixel electrode 102.

The pixel electrode 102 includes: a first pixel electrode portion 102 aopposed to the domains 101 a and 101 b along the thickness direction ofthe pixel electrode 102 (i.e., a direction perpendicular to the plane ofthe figure of FIG. 4); and a second pixel electrode portion 102 bopposed to the domains 101 c and 101 d along the thickness direction ofthe pixel electrode 102. Between the first pixel electrode portion 102 aand the second pixel electrode portion 102 b, a bridging portion 102 cis provided.

The first pixel electrode portion 102 a includes: a first slitted region111 opposed to the domain 101 a along the thickness direction of thepixel electrode 102; and a second slitted region 121 opposed to thedomain 101 b along the thickness direction of the pixel electrode 102.

In the first slitted region 111, eight slits 112A, 112B, . . . , 112Hextending along a direction parallel to the alignment azimuth of theliquid crystal molecules 41 in the domain 101 a are formed.

The slits 112A, 112B, . . . , 112H are mutually equal in width, whilebeing set to mutually different lengths. The width of the slits 112A,112B, . . . , 112H is set to e.g. 3.0 μm. The interval between the slits112A, 112B, . . . , 112H is also set to e.g. 3.0 μm. In other words, thedesign pitch of the slits 112A, 112B, . . . , 112H may be set to e.g.6.0 μm. Note that, in terms of improving transmittance of the pixel 101the design pitch is preferably e.g. 7.0 μm or less, and in terms offacilitating fabrication the design pitch is preferably e.g. 5.2 μm ormore.

In the second slitted region 121, eight slits 122A, 122B, . . . , 122Hextending along a direction parallel to the alignment azimuth of theliquid crystal molecules in the domain 101 b are formed.

The slits 122A, 122B, . . . , 122H also are mutually equal in width,while being set to mutually different lengths. The width of the slits122A, 122B, . . . , 122H is set to the same width as the width of theslits 112A, 112B, . . . , 112H. Moreover, the interval between the slits122A, 122B, . . . , 122H is also set to the same interval as theinterval between the slits 112A, 112B, . . . , 112H. Note that, in termsof improving transmittance of the pixel 101, the design pitch of theslits 122A, 122B, . . . , 122H also is e.g. 7.0 μm or less, and in termsof facilitating fabrication the design pitch is preferably e.g. 5.2 μmor more.

Moreover, no slits are formed in the region between the slits 112A,112B, . . . , 112H and the slits 122A, 122B, . . . , 122H.

The second pixel electrode portion 102 b includes: a first slittedregion 141 opposed to the domain 101 c along the thickness direction ofthe pixel electrode 102; and a second slitted region 151 opposed to thedomain 101 d along the thickness direction of the pixel electrode 102.

In the first slitted region 141, eight slits 142A, 142B, . . . , 142Hextending along a direction parallel to the alignment azimuth of theliquid crystal molecules 41 in the domain 101 c are formed.

The slits 142A, 142B, . . . , 142H are mutually equal in width, whilebeing set to mutually different lengths. The width of the slits 142A,142B, . . . , 142H is set to e.g. 3.0 μm. Moreover, the interval betweenthe slits 142A, 142B, . . . , 142H is also set to e.g. 3.0 μm. In otherwords, the design pitch of the slits 142A, 142B, . . . , 142H is set toe.g. 6.0 μm. Note that, in terms of improving transmittance of the pixel101 the design pitch is preferably e.g. 7.0 μm or less, and in terms offacilitating fabrication the design pitch is preferably e.g. 5.2 μm ormore.

In the second slitted region 151, eight slits 152A, 152B, . . . , 152Hextending along a direction parallel to the azimuth of the liquidcrystal molecules in the domain 101 b are formed.

The slits 152A, 152B, . . . , 152H also are mutually equal in width,while being set to mutually different lengths. The width of the slits152A, 152B, . . . , 152H is set to the same width as the width of theslits 142A, 142B, . . . , 142H. Moreover, the interval between the slits152A, 152B, . . . , 152H is set to the same interval as the intervalbetween the slits 142A, 142B, . . . , 142H. Note that, in terms ofimproving transmittance of the pixel 101, the design pitch of the slits152A, 152B, . . . , 152H also is e.g. 7.0 μm or less, and in terms offacilitating fabrication the design pitch is preferably e.g. 5.2 μm ormore.

Moreover, no slits are formed in the region between the slits 142A,142B, . . . , 142H and the slits 152A, 152B, . . . , 152H.

The bridging portion 102 c is a portion that connects between the firstpixel electrode portion 102 a and the second pixel electrode portion 102b. When a center line C101 which extends along the longitudinaldirection of the pixel 101 and which passes through a center of thewidth direction of the pixel electrode 102 is defined, the bridgingportion 102 c overlaps the center line C101.

Moreover, a first recess 102 d is provided at one side along the widthdirection of the pixel electrode 102. Between the first pixel electrodeportion 102 a and the second pixel electrode portion 102 b, the firstrecess 102 d extends from one side along the width direction of thepixel electrode 102 toward the bridging portion 102 c.

Moreover, a second recess 102 e is provided at the other side along thewidth direction pixel electrode 102. Between the first pixel electrodeportion 102 a and the second pixel electrode portion 102 b, the secondrecess 102 e extends from the other side along the width direction ofthe pixel electrode 102 toward the bridging portion 102 c.

Moreover, the first recess 102 d, the bridging portion 102 c, and thesecond recess 102 e are arranged along the width direction of the pixelelectrode 102. The width of the first recess 102 d is set equal to thewidth of the second recess 102 e. For example, the width of the firstand second recesses 102 d and 102 e is set so as to fall within therange of e.g. 4.0 to 5.0 μm. To explain more specifically, one side ofthe first recess 102 d that is closer to the second pixel electrodeportion 102 b is aligned in position with one side of the second recess102 e that is closer to the second pixel electrode portion 102 b, alongthe width direction of the pixel electrode 102. In other words, one sideof the first recess 102 d that is closer to the second pixel electrodeportion 102 b is collinear with one side of the second recess 102 e thatis closer to the second pixel electrode portion 102 b. Similarly, oneside of the first recess 102 d that is closer to the first pixelelectrode portion 102 a is collinear with one side of the second recess102 e that is closer to the first pixel electrode portion 102 a.

Moreover, no slits are formed in the region between the first and secondrecesses 102 d and 102 e and the slits 122A, 122B, . . . , 122E. Inother words, the first and second recesses 102 d and 102 e are formed inthe pixel electrode 102 so as to have a predetermined interval with theslits 122A, 122B, . . . , 122H.

Moreover, no slits are formed in the region between the first and secondrecesses 102 d and 102 e and the slits 142D, 142E, . . . , 142H. Inother words, the first and second recesses 102 d and 102 e are formed inthe pixel electrode 102 so as to have a predetermined interval with theslits 142A, 142B, . . . , 142H.

With the liquid crystal display panel of the above configuration, when avoltage is applied to the liquid crystal layer 30, a double dark lineoccurs in a portion between the first pixel electrode portion 102 a andthe second pixel electrode portion 102 b. Since the bridging portion 102c and the first and second recesses 102 d and 102 e are provided betweenthe first pixel electrode portion 102 a and the second pixel electrodeportion 102 b, the geometric area of the double dark line can bereduced. As a result, the pixel 101 can attain an adequate transmittancewith a simple configuration.

Moreover, since the bridging portion 102 c is formed so as to overlapthe center line C101, a disclination in the double dark line can becaused on the central portion of the width direction of the pixelelectrode 102. Thus, variation in the sites of occurrence of adisclination in the double dark line can be suppressed.

FIG. 5 is a photographic representation of one pixel, illustrating aresult of simulating occurrence of dark lines in the first embodiment.In FIG. 5, liquid crystal molecules 41 under an applied voltage acrossthe liquid crystal layer 30 are depicted as bolt shapes. Morespecifically, heads of the bolts correspond to bottoms of the cones inFIG. 2 and FIG. 3. On the other hand, ends of the bolts opposite totheir heads, i.e., the tips, correspond to apices of the cones in FIG. 2and FIG. 3.

It can be seen from FIG. 5 that although a double dark line extendsalong the transverse direction of the pixel 101, an increase in thegeometric area of this double dark line is suppressed.

It can also be seen that a disclination P101 has occurred above thecentral portion of the width direction of the pixel electrode 102.

FIG. 6 is an enlarged plan view of a pixel electrode 2102 according toComparative Example for this invention and its neighborhood.

The pixel electrode 2102 corresponds to the pixel electrode 102, fromwhich the first and second recesses 102 d and 102 e are eliminated. Inother words, the pixel electrode 2102 differs from the pixel electrode102 only because of lacking the first and second recesses 102 d and 102e.

FIG. 7 is a photographic representation of one pixel in the case wherethe pixel electrode 2102 according to Comparative Example is used in theplace of the pixel electrode 102 according to the first embodiment,illustrating a result of simulating occurrence of dark lines. In FIG. 7,similarly to FIG. 5, liquid crystal molecules 41 under an appliedvoltage across the liquid crystal layer 30 are depicted as bolt shapes.

It can be seen from FIG. 7 that a disclination P2101 occurs as in thefirst embodiment, but a double dark line that extends toward thedisclination P2101 is thicker than that in the first embodiment.

Thus, it can be seen that the transmittance of the pixel 101 accordingto the first embodiment can be made higher than the transmittance of thepixel 101 according to Comparative Example.

The first embodiment illustrates that the alignment azimuths of theliquid crystal molecules 41 in the domains 101 a, 101 b, 101 c and 101 dare substantially 135°, 225°, 45° and 315°; however, they may besubstantially 45°, 315°, 135° and 225°, for example.

The first embodiment illustrates that eight slits are formed in each ofthe first slitted regions 111 and 141 and in each of the second slittedregions 121 and 151; alternatively, any plurality, other than eight, ofthem may be formed. In other words, the number of slits is not limitedto that in the first embodiment. Moreover, the width and length of theslits are not limited to those in the first embodiment.

The first embodiment illustrates that the width of the first recess 102d is set equal to the width of the second recess 102 e; however, it maybe set larger than the width of the second recess 102 e, or smaller thanthe width of the second recess 102 e.

In the first embodiment, the polarization axis of the first polarizer 60is parallel to the transverse direction of the pixels 101, and thepolarization axis of the second polarizer 70 is parallel to thelongitudinal direction of the pixels 101. However, the polarization axisof the first polarizer 60 may be parallel to the longitudinal directionof the pixels 101, while the polarization axis of the second polarizer70 may be parallel to the transverse direction of the pixels 101.

The first embodiment illustrates that the capacitor line 18 is formed soas to overlap the end of the pixel electrode 102 that is closer to thethin film transistor 13, as shown in FIG. 8; however, a capacitor line118 may be formed so as to overlap the bridging portion 102 c and thefirst and second recesses 102 d and 102 e of the pixel electrode 102.When this is adopted, as shown in FIG. 9, transmittance will decreaserelative to the first embodiment, but the longer distance between thegate line 14 and the capacitor line 118 allows for an enhancedproducibility.

Second Embodiment

Hereinafter, a liquid crystal display panel according to a secondembodiment of this invention will be described, where any constituentelements that are identical to constituent element of the firstembodiment will be denoted by identical reference numerals to those ofthe constituent elements in the first embodiment.

FIG. 10 is a plan view showing enlarged a pixel electrode 202 includedin a liquid crystal display panel according to a second embodiment ofthis invention, and its neighborhood.

The liquid crystal display panel according to the second embodimentdiffers from the liquid crystal display panel according to the firstembodiment in that it includes the pixel electrode 202 instead of thepixel electrode 102. In the liquid crystal display panel according tothe second embodiment, any portion other than the pixel electrode 202 isconfigured similarly to its counterpart in the liquid crystal displaypanel according to the first embodiment.

The pixel electrode 202 includes: a first pixel electrode portion 202 aopposed to the domains 101 a and 101 b along the thickness direction ofthe pixel electrode 202 (i.e., a direction perpendicular to the plane ofthe figure of FIG. 10); and a second pixel electrode portion 202 bopposed to the domains 101 c and 101 d along the thickness direction ofthe pixel electrode 202. Between the first pixel electrode portion 202 aand the second pixel electrode portion 202 b, a bridging portion 202 cis provided.

At its side closer to the second pixel electrode portion 202 b, thefirst pixel electrode portion 202 a includes a second slitted region221, the second slitted region 221 facing the domain 101 b in thethickness direction of the pixel electrode 202.

In the second slitted region 221, two slits 222A, 222B and six slits122C, 122D, . . . , 122H extending along a direction parallel to thealignment azimuth of the liquid crystal molecules in the domain 101 bare formed. Note that the slits 222A to 222H are examples of secondslits.

Along a direction parallel to the liquid crystal molecules in the domain101 b, the slits 222A, 222B are formed so as to be longer than the slits122A, 122B. As a result of this, the ends of the slits 222A, 222B thatare closer to the second pixel electrode portion 202 b are locatednearer the second pixel electrode portion 202 b than are the ends of thesix slits 122C, 122D, . . . , 122H that are closer to the second pixelelectrode portion 202 b. Moreover, the width and the design pitch of theslits 222A, 222B are set similar to those of the slits 122A, 122B. Inthis case, the width and the design pitch of the slits 222A, 222B may besaid to be similar to the width and the design pitch of the six slits122C, 122D, . . . , 122H.

Moreover, the ends of the slits 222A, 222B that are closer to thebridging portion 202 c are aligned in position along the width directionof the pixel electrode 202. The ends of the slits 122C, 122D, 122E thatare closer to the bridging portion 202 c also are aligned in positionalong the width direction of the pixel electrode 202. Furthermore, theends of the slits 222A, 222B that are closer to the bridging portion 202c are located nearer the bridging portion 202 c than are the ends of theslits 122C, 122D, 122E that are closer to the bridging portion 202 c. Inother words, the ends of the slits 222A, 222B that are closer to thebridging portion 202 c are disposed relatively near the bridging portion202 c, while the ends of the slits 122C, 122D, 122E that are closer tothe bridging portion 202 c are disposed relatively far from the bridgingportion 202 c. In other words, the ends of the slits 222A, 222B that arecloser to the bridging portion 202 c are provided so as to protrudetoward the second pixel electrode portion 202 b relative to the ends ofthe slits 122C, 122D, 122E that are closer to the bridging portion 202c. In the meantime, the distance between the ends of the slits 222A,222B that are closer to the bridging portion 202 c and the first recess202 d is equal or essentially equal to the distance between the ends ofthe slits 122C, 122D, 122E that are closer to the bridging portion 202 cand the second recess 202 e.

At its side closer to the first pixel electrode portion 202 a, thesecond pixel electrode portion 202 b includes a first slitted region241, the first slitted region 241 facing the domain 101 c in thethickness direction of the pixel electrode 202.

In the first slitted region 241, six slits 142A, 142B, . . . , 142F, andtwo slits 242G, 242H extending along a direction parallel to thealignment azimuth of the liquid crystal molecules 41 in the domain 101 care formed.

Along a direction parallel to the alignment azimuth of the liquidcrystal molecules 41 in the domain 101 c, the slits 242G, 242H areformed so as to be longer than the slits 142G, 142H. As a result ofthis, the ends of the slits 242G, 242H that are closer to the firstpixel electrode portion 202 a are located nearer the first pixelelectrode portion 202 a than are the ends of the slits 142A, 142B, . . ., 142F that are closer to the first pixel electrode portion 202 a.Moreover, the width and the design pitch of the slits 242G, 242H are setsimilar to those of the slits 142G, 142H. In this case, the width andthe design pitch of the slits 242G, 242H may be said to be similar tothe width and the design pitch of the slits 142A, 142B, . . . , 142F.

Moreover, the ends of the slits 142D, 142E, 142F that are closer to thebridging portion 202 c are aligned in position along the width directionof the pixel electrode 202. The ends of the slits 242G, 242H that arecloser to the bridging portion 202 c also are aligned in position alongthe width direction of the pixel electrode 202. Furthermore, the ends ofthe slits 242G, 242H that are closer to the bridging portion 202 c arelocated nearer the bridging portion 202 c than are the ends of the slits142D, 142E, 142F that are closer to the bridging portion 202 c. In otherwords, the ends of the slits 142A, 142B, . . . , 142F that are closer tothe bridging portion 202 c are disposed relatively far from the bridgingportion 202 c, while the ends of the slits 242G, 242H that are closer tothe bridging portion 202 c are disposed relatively near the bridgingportion 202 c. In other words, the ends of the slits 242G 242H that arecloser to the bridging portion 202 c are provided so as to protrudetoward the first pixel electrode portion 202 a relative to the ends ofthe slits 142D, 142E, 142F that are closer to the bridging portion 202c. In the meantime, the distance between the ends of the slits 142D,142E, 142F that are closer to the bridging portion 202 c and the firstrecess 202 d is equal or essentially equal to the distance between theends of the slits 242G, 242H that are closer to the bridging portion 202c and the second recess 202 e.

Moreover, the distance between the ends of the slits 222A, 222B that arecloser to the bridging portion 202 c and the ends of the slits 142D,142E that are closer to the bridging portion 202 c is equal oressentially equal to the distance between the ends of the slits 122D,122E that are closer to the bridging portion 202 c and the ends of theslits 242G, 242H that are closer to the bridging portion 202 c.

The bridging portion 202 c is a portion that connects between the firstpixel electrode portion 202 a and the second pixel electrode portion 202b. When a center line C201 which extends along the longitudinaldirection of the pixel 101 and which passes through a center of thewidth direction of the pixel electrode 202 is defined, the bridgingportion 202 c overlaps the center line C201.

Moreover, the first recess 202 d is provided at one side along the widthdirection of the pixel electrode 202. Between the first pixel electrodeportion 202 a and the second pixel electrode portion 202 b, the firstrecess 202 d extends from the one side along the width direction of thepixel electrode 202 toward the bridging portion 202 c.

Moreover, the second recess 202 e is provided at the other side alongthe width direction of the pixel electrode 202. Between the first pixelelectrode portion 202 a and the second pixel electrode portion 202 b,the second recess 202 e extends from the other side along the widthdirection of the pixel electrode 202 toward the bridging portion 202 c.

Moreover, the first recess 202 d is not aligned in position with thesecond recess 202 e along the width direction of the pixel electrode202. Moreover, the width of the first recess 202 d is set equal to thewidth of the second recess 202 e. For example, the width of the firstand second recesses 202 d and 202 e is set so as to fall within therange of e.g. 4.0 to 5.0 μm. To explain more specifically, one side ofthe first recess 202 d that is closer to the second pixel electrodeportion 202 b is located nearer the thin film transistor 13 (i.e.,nearer one end of the longitudinal direction of the pixel electrode 202)than is one side of the second recess 202 e that is closer to the secondpixel electrode portion 202 b. Similarly, one side of the first recess202 d that is closer to the first pixel electrode portion 202 a islocated nearer the thin film transistor 13 than is one side of thesecond recess 202 e that is closer to the first pixel electrode portion202 a. Conversely stated, one side of the second recess 202 e that iscloser to the second pixel electrode portion 202 b is located moretoward the opposite side from the thin film transistor 13 (i.e., nearerthe other end of the longitudinal direction of the pixel electrode 202)than is one side of the first recess 202 d that is closer to the secondpixel electrode portion 202 b. Moreover, one side of the second recess202 e that is closer to the first pixel electrode portion 202 a islocated more toward the opposite side from the thin film transistor 13than is one side of the first recess 202 d that is closer to the firstpixel electrode portion 202 a.

With the liquid crystal display panel of the above configuration, thebridging portion 202 c and the first and second recesses 202 d and 202 eare provided between the first pixel electrode portion 202 a and thesecond pixel electrode portion 202 b, the bridging portion 202 coverlapping the center line C201, whereby action and effects similar tothose of the first embodiment are attained.

Moreover, the position of the first recess 202 d and the position of thesecond recess 202 e are not aligned along the width direction of thepixel electrode 202, whereby an enhanced effect of reducing thegeometric area of dark lines can be obtained.

FIG. 11 is a photographic representation of one pixel of the secondembodiment, illustrating a result of simulating occurrence of darklines. In FIG. 11, liquid crystal molecules 41 under an applied voltageacross the liquid crystal layer 30 are depicted as bolt shapes. Morespecifically, heads of the bolts correspond to bottoms of the cones inFIG. 2 and FIG. 3. On the other hand, ends of the bolts opposite totheir heads, i.e., the tips, correspond to apices of the cones in FIG. 2and FIG. 3.

It can be seen from FIG. 11 that a disclination P201 has occurred abovethe bridging portion 202 c and that although the double dark lineextends along the transverse direction of the pixel 101, an increase inthe geometric area of this double dark line is suppressed.

The second embodiment illustrates that the capacitor line 18 is formedso as to overlap the end of the pixel electrode 202 that is closer tothe thin film transistor 13; however, as shown in FIG. 12, a capacitorline 218 may be formed so as to overlap the bridging portion 202 c andthe first and second recesses 202 d and 202 e of the pixel electrode202. When this is adopted, as shown in FIG. 13, transmittance willdecrease relative to the second embodiment, but the longer distancebetween the gate line 14 and the capacitor line 218 allows for anenhanced producibility.

Although specific embodiments of this invention have been described,this invention is not to be limited to the above-described first andsecond embodiments and variations thereof; rather, this invention can bepracticed with various alterations within its scope. For example, someof the details described in the first and second embodiments may bedeleted or replaced to provide an embodiment of this invention.Moreover, alterations as described for the first embodiment may beapplied to the second embodiment to provide an embodiment of thisinvention.

Moreover, description of Japanese Patent No. 5184618, Japanese Laid-OpenPatent Publication No. 2011-85738, and International Publication No.2017/047532 is also applicable to the liquid crystal display panel ofthis invention. For example, as examples of materials and productionmethods of liquid crystal display panels according to this invention,the materials and production methods, etc., described in Japanese PatentNo. 5184618 Japanese Laid-Open Patent Publication No. 2011-85738, andInternational Publication No. 2017/047532 can be adopted.

That is, the above disclosure can be summarized as follows.

A liquid crystal display panel according to one implementation of thisinvention is a liquid crystal display panel having a display mode thatis a VA mode, comprising:

a plurality of rectangular-shaped pixels 101;

a first substrate section 10 including a first substrate 11 and pixelelectrodes 102, 202;

a liquid crystal layer 30 provided on the first substrate section 10,the liquid crystal layer 30 containing liquid crystal molecules 41; and

a second substrate section 50 provided on the liquid crystal layer 30,the second substrate section 50 including a second substrate 51 and acounter electrode 103, wherein,

the plurality of pixels 101 each include a first domain 101 a, a seconddomain 101 b, a third domain 101 c, and a fourth domain 101 d arrangedalong a longitudinal direction of the pixel 101,

when a direction orthogonal to the longitudinal direction of the pixel101 is defined as a transverse direction of the pixel 101 and an azimuthflush with this transverse direction is defined as 0°, an alignmentazimuth of the liquid crystal molecules 41 in the second domain 101 b issubstantially 225° and an alignment azimuth of the liquid crystalmolecules 41 in the third domain 101 c is substantially 45°; or analignment azimuth of the liquid crystal molecules 41 in the seconddomain 101 b is substantially 315° and an alignment azimuth of theliquid crystal molecules 41 in the third domain 101 c is substantially135°,

each pixel electrode 102, 202 includes

a first pixel electrode portion 102 a, 202 a facing the first and seconddomains 101 a, 101 b in a thickness direction of the pixel electrode102, 202,

a second pixel electrode portion 102 b, 202 b facing the third andfourth domains 101 c, 101 d in the thickness direction of the pixelelectrode 102, 202, and

a bridging portion 102 c, 202 c being provided between the first pixelelectrode portion 102 a, 202 a and the second pixel electrode portion102 b, 202 b and linking together the first pixel electrode portion 102a, 202 a and the second pixel electrode portion 102 b, 202 b;

a first recess 102 d, 202 d is provided at one side along a widthdirection of the pixel electrode 102, 202, the first recess 102 d, 202 dextending from the one side along the width direction of the pixelelectrode 102, 202 toward the bridging portion 102 c, 202 c and beinglocated between the first pixel electrode portion 102 a, 202 a and thesecond pixel electrode portion 102 b, 202 b; and

a second recess 102 e, 202 e is provided at another side along the widthdirection of the pixel electrode 102, 202, the second recess 102 e, 202e extending from the other side along the width direction of the pixelelectrode 102, 202 toward the bridging portion 102 c, 202 c and beinglocated between the first pixel electrode portion 102 a, 202 a and thesecond pixel electrode portion 102 b, 202 b.

With the above configuration, the first recess 102 d, 202 d is providedat one side along the width direction of the pixel electrode 102, 202.The first recess 102 d, 202 d extends from one side along the widthdirection of the pixel electrode 102, 202 toward the bridging portion102 c, 202 c, and is located between the first pixel electrode portion102 a, 202 a and the second pixel electrode portion 102 b, 202 b. On theother hand, the second recess 102 e, 202 e is provided at the other sidealong the width direction of the pixel electrode 102, 202. The secondrecess 102 e, 202 e extends from the other side along the widthdirection of the pixel electrode 102, 202 toward the bridging portion102 c, 202 c, and is located between the first pixel electrode portion102 a, 202 a and the second pixel electrode portion 102 b, 202 b. Inother words, regarding the bridging portion 102 c, 202 c, the firstrecess 102 d, 202 d is provided at one side along the width direction ofthe pixel electrode 102, 202, and the second recess 102 e, 202 e isprovided at the other side along the width direction of the pixelelectrode 102, 202. As a result, when a voltage is applied to the liquidcrystal layer 30, the geometric area of dark lines occurring near theboundary between the second domain 101 b and the third domain 101 c canbe reduced. Therefore, the aforementioned pixel 101 can attain anadequate transmittance with a simple configuration.

In a liquid crystal display panel according to one embodiment,

when a center line C101, C201 which extends along the longitudinaldirection of the pixel 101 and which passes through a center of thewidth direction of the pixel electrode 102, 202 is defined, the bridgingportion 102 c, 202 c overlaps the center line C101, C201.

According to the above embodiment, because the bridging portion 102 c,202 c overlaps the center line C101, C201, variation in the sites ofoccurrence of a disclination P101, P201 in the dark line(s) can besuppressed.

In a liquid crystal display panel according to one embodiment,

the first recess 202 d is not aligned in position with the second recess202 e along the width direction of the pixel electrode 202.

According to the above embodiment, because the position of the firstrecess 202 d and the position of the second recess 202 e are not alignedalong the width direction of the pixel electrode 202, an enhanced effectof reducing the geometric area of dark lines can be obtained.

REFERENCE SIGNS LIST

first substrate section,

11 first glass substrate

20 first vertical alignment film

30 liquid crystal layer

41 liquid crystal molecule

40 second vertical alignment film

50 second substrate section

51 second glass substrate

90 sealing member

101 pixel

101 a, 101 b, 101 c, 101 d domain

102, 202 pixel electrode

103 counter electrode

102 a, 202 a first pixel electrode portion

102 b, 202 b second pixel electrode portion

102 c, 202 c bridging portion

102 d, 202 d first recess

102 e, 202 e second recess

111, 141, 211, 241 first slitted region

112A to 112H, 122A to 122H, 142A to 142H, 152A to 152H, 222A, 222B,242G, 242H slit

121, 152, 221, 252 second slitted region

C101, C201 center line

P101, P201, P2101 disclination

The invention claimed is:
 1. A liquid crystal display panel having adisplay mode that is a VA mode, comprising: a plurality ofrectangular-shaped pixels; a first substrate section including a firstsubstrate and pixel electrodes; a liquid crystal layer provided on thefirst substrate section, the liquid crystal layer containing liquidcrystal molecules; and a second substrate section provided on the liquidcrystal layer, the second substrate section including a second substrateand a counter electrode, wherein, the plurality of pixels each include afirst domain, a second domain, a third domain, and a fourth domainarranged along a longitudinal direction of the pixel, when a directionorthogonal to the longitudinal direction of the pixel is defined as atransverse direction of the pixel and an azimuth flush with thetransverse direction of the pixel is defined as 0°, an alignment azimuthof the liquid crystal molecules in the second domain is substantially225° and an alignment azimuth of the liquid crystal molecules in thethird domain is substantially 45°, or an alignment azimuth of the liquidcrystal molecules in the second domain is substantially 315° and analignment azimuth of the liquid crystal molecules in the third domain issubstantially 135°, each pixel electrode includes a first pixelelectrode portion facing the first and second domains in a thicknessdirection of the pixel electrode, a second pixel electrode portionfacing the third and fourth domains in the thickness direction of thepixel electrode, a bridging portion being provided between the firstpixel electrode portion and the second pixel electrode portion andlinking together the first pixel electrode portion and the second pixelelectrode portion, a first recess being provided at one side along awidth direction of the pixel electrode, the first recess extendingtoward the bridging portion along the width direction of the pixelelectrode and being located between the first pixel electrode portionand the second pixel electrode portion, and a second recess beingprovided at another side along the width direction of the pixelelectrode, the second recess extending toward the bridging portion alongthe width direction of the pixel electrode and being located between thefirst pixel electrode portion and the second pixel electrode portion,when a center line which extends along the longitudinal direction of thepixel and which passes through a center of the width direction of thepixel electrode is defined, the bridging portion overlaps the centerline, the first recess is not aligned in position with the second recessalong the width direction of the pixel electrode.